Chances are, what you’ve been taught all your life about fats and oils is completely upside-down. In the 1960’s, a man named Ancel Keys did a study. He misrepresented the findings of this study so it appeared to demonstrate that dietary cholesterol and saturated fat lead to atherosclerosis (hardening of the arteries) and heart disease.
This notion caught on, and ever since, government agencies like the United States Department of Agriculture (USDA) and large medical agencies have been pushing for the avoidance of animal fats and other saturated fats, and their replacement with vegetable oils – which, for a long time, included hydrogenated oils (oils which are naturally liquid at room temperature but have been altered with hydrogen atoms to make them solid) such as margarine and vegetable shortening.
The problem is, this idea was never true. Keys conveniently omitted all the data from countries that didn’t fit his theory! (1) Man has been consuming animal fats from the beginning, and heart disease as we know it today was not a widespread issue until fairly recently. The fat isn’t what changed. The science – and anthropological evidence – support a different theory: that an excess of refined carbohydrates (e.g. white bread and sugar) is the primary contributor to heart disease.
Now, we do often find high blood cholesterol levels when heart disease is present. More and more, though, researchers are coming to suspect this increase in cholesterol is a protective mechanism to minimize the damage to weakened arteries. If you artificially decrease the cholesterol without fixing the true cause, that’s a little like dragging all the firefighters away from the scene of a fire: bad news.(1) Under normal circumstances, a healthy body will regulate its own cholesterol levels, making more if you’re eating less and making less if you’re eating more.
If saturated fat isn’t bad, then what about liquid vegetable oils? Well, they’re not as ideal as we’ve been led to believe. In fact, the USDA’s own data show that the consumption of animal fats decreased and the consumption of vegetable oils increased during the decades when heart disease was going up!(2)
Typical vegetable oils have a number of issues. First, most are very high in Omega-6 fatty acids. We need Omega-6’s, but we also need Omega-3’s, and the average modern diet has way too high a ratio of Omega-6’s to Omega-3’s. A high intake of vegetable oils contributes to this upside-down ratio, increasing inflammation with all of its negative consequences and likely even the risk of cancer. Dr. Shanahan’s Deep Nutrition has an entire chapter about the negative impact of vegetable oils on the brain alone. When you stop to think about it, much of the “vegetable oil” used today isn’t even from plant parts we would consider edible!
I’ll give more specific examples in a moment, but first let me offer you my personal, common-sense rule of thumb: is this something that probably would have been eaten a few hundred years ago? If it depends on high-tech modern methods to even exist, it probably isn’t something intended for food. If it is (or could be) produced by traditional methods, it’s probably a real food.